Some variation in Acacia auriculiformis and its breeding strategy

  • Haruo Ogihara

    Student thesis: Masters by Research - CDU


    Acacia auricithformis has two types of flower, big (exceeding 4.0 mm) andsmall (less than 4.0 mm). The rachis size can be also divided into long(exceeding 8.0 cm) and short (less than 8.0 cm). Big flowers were present onboth long and short rachis but small flowers were found only on short rachis. 

    There are male flowers and bisexual flowers in A. auriculformis. The sexratio (percent of male flowers) varied enormously between branches and maleflowers were distributed randomly along the rachis. The proportion of maleflowers present on an inflorescence was normally less than 10%, however thissex ratio changed dramatically within a short time (two weeks). 

    Most of the rachis reached full size in 6-8 weeks. But there was no typicalpattern of growth. The pattern of growth was different for each tree.

    The start of flowering occurred at 2200-2400 h and the flower was fullyopened at 0400-0600 h. The flowering sequence can be divided into fourstages. 

    Most pollination occurred in the morning, none at night. About 40% offlowers were pollinated during a day. 
    Fruit set varied between trees and season. However rachises containedonly one fruit. 

    Seed size and weight varied between trees. Most viable seed did not imbibewithin four weeks and those that had imbibed did not show good viability.  

    Date of Award1999
    Original languageEnglish

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